While I've already put a bunch of effort (and money) into the tumbling idea, I'm having second thoughts. A combination of the others might be easier.

In detail, the options:

Pressure washing: I have a gas 4000 psi washer that I can throw on my truck and drive over to HF. If we can get the compressor back over to the dock area, we can just hose it out. Pretty simple, really.

Reverse electrolysis:We stick a sacrificial anode (like a piece of rebar) into the tank, used as an electrode. We put electrolyte in the tank, then run DC current through the body of the tank. This will pull the rust off the inside of the tank and deposit it on the rebar.

Tumbling with acid:Probably the most complicated and work-intensive option, which for some reason attracted my attention. This requires removal of the motor, compressor, piping and everything else bolted onto the tank. Probably the most thorough of the options. After the tank is stripped bare, we put 5-10 pounds of nuts/bolts in, along with several gallons of acid. We gently spin the tank on a homemade roller setup, causing the acid and nuts/bolts to churn and bounce around inside, knocking loose all the cruft.

While I originally thought #3 was the best option, doing #1 and then #2 in order would be faster and easier.

Ideas? Thoughts?

P.S. A big thanks to Nick for cutting the axle holders for the tumbling setup on his plasma cutter. If we go that route, they'll be used to hold the wheels up. There's still a lot more work to do on the tumbling jig if we decide to go that route.

Well, the real question is, once you get the tank all squeaky clean and rust free on the inside, what happens then? Once you start running it the compressor pump basically sprays a mix of water and whatever oil gets past the rings into the tank, and it starts rusting again. That's why filters are generally installed upstream of the regulators at the point of use.

My experience has been that the crud mostly just lays around in the bottom of the tank.

While any machine gunks up, the issue here is whether it has two years of life left, or twelve. I think Peter's efforts are intended toward skewing the life toward the upper end of that scale. Time well spent; although...

I want to take a step further back and ask: "Where is this enormous, and probably incredibly loud, thing going to live when it's up and running?". All efforts will be for naught if, as I suspect, it's louder than the table saw when it's cutting (but perhaps not as loud as the planer when it was dull and planing oak planks).

I've suggested a few ideas, including building a shed for it, but I don't know if any of those really are feasible. Personally I advocate doing some minimal work, involving elbow grease and little to no financial expense, and see just how well, and how loud, it runs. Then we decide where it will live, or perhaps we sell a partially reconditioned compressor at a profit. And then we can do more advanced reconditioning work based on that decision.

I believe that the plan is , or should be to change the oil, clean the filter and fire it up, We've been waiting an awfully long time to get some 3 phase power going. I'm guessing it still hasn't happened yet, but as soon as it does we can fire Curtis up and get a feel for the volume etc.

I've been running this 15HP Ingersoll Rand for over 20 years now, and it wasn't brand new when I got it. Every summer I drain 20 or 30 gallons of nasty looking water out of it. It hasn't missed a beat. Pete's got the right plan. Change the oil, wire it up and go.

Yes it's gonna be loud as hell, and hot, too, if 2 people are running air-hog tools like grinders in the heat of summer. To stop the sound you need something with some mass, like maybe cement board, and a big blower to get cooling air in the enclosure. It's a beautiful thing, though, to have enough power to run a cold air gun *and* a big grinder at the same time.

Eventually you'll want a refrigerated dryer, but moisture won't be a problem until late April.

Hearing little in the way of complaint, I'll let off on the tumbling/acid idea.

Let's just pressure wash it to get the rest of the gunk out, then power it up.

I'll wait on Jude/John/etc for a decision on where we can get power to it (not necessarily where it'll permanently live), but we need to get it over to the dock to get it washed out - I only have 40-50 feet of high pressure hose.

Once it's over by the dock, there is 3 phase power being used by the miller welder, for testing purposes(I'm thinking like at most a couple of hours) we could disconnect the miller welder wires from the blade switch and hook in the compresser to see how/if it works.

It's should be possible to hook up to one of the other boxes in the ceiling as well for testing purposes.